Mine roof supports



June 8, 1965 F. TOWN MINE ROOF SUPPORTS 3 Sheets-Sheet 1 Filed Nov. 15, 1962 INVENTOR Fra/ZK 701w? ATTORNEY June 8, 1965 ow 3,188,041

' MINE ROOF SUPPORTS Filed NOV- 15, 1962 3 Sheets-Sheet 2 I n illul' i A T; Wa /1 INVENTOR Frank Tow/2 ATTORNEY Julie 8, 1965 Filed Nov. 15, 1962 F. TOWN MINE ROOF SUPPORTS 3 Sheets-Sheet 3 INVENTOR Fra/IK W Mm wm ATTORNEY United States Patent 3,188,041 MINE ROGF SUIPORTS Frank Town, Burton .lo-yce, England, assignor to W. E. & F. Dobson Limited Filed Nov. 15, 1962, Ser. No. 237,869 Claims priority, application Great Britain, Nov. 21., 1961,

10 Claims. (Cl. 248-656) This invention is for improvements in or relating to mine roof supports having or comprising pit props, and primarily hydraulic pit props;

In the use of these mine roof supports, particularly in the instance where a plurality of pit props are mounted on 'a common base, the tendency for the props to tilt over after a period of use, due to movements of the root, can result in the disadvantage that the tilt becomes permanent rendering the support unfit for continued use.

In order to avoid this disadvantage it is known for a pit prop to have a rubber buffer ring incorporated in it between inner and outer tubular portions of the prop, but in use this construction is not entirely satisfactory.

An object of the invention is to provide a boiler element in a pit prop in improved manner.

The invention provides a mine root sup-port having or comprising a pit prop primarily of hydraulic type and a rubber or the like buffer. ring secured between upper and lower metal plates one of which is relatively stationary, and the other of which is tiltable with tilting movements of the prop. Conveniently the metal plates are initially parallel so that after tilting of the prop out of centralized position it is returned by the-buffer sing to the centralized position. The butter ring may be secure-d to the metal plates by circurnterentially spaced bolts by which the buffer ring can be pre-stressed and form an effective seal, the bolts being adjustable at any time to tighten the seal or to p-re-set the propinto tilted attitude, if desired.

The buffer ring may be secured either directly to the metal plates by the bolts, or there may be intermediate metal plates, some bolts securing one of the outer metal plates to the intermediate metal plates and other bolts securing the other outer metal plate to the intermediate metal plates.

In another alternative the butter ring is bonded between intermediate metal plates, these metal plates being secured respectively by screws or bolts to the outer metal plates.

The invention also provides a mine roof support having a base bearing for the lower end of a pit prop, a lower metal plate supported from the base bearing and extending around the prop, a rubber or the like buffer ring .disposed on the lower metal plate and encircling the prop, a tubular member encircling the propclosely at its upper end and having at its lower end an annular metal ring encircling the prop and disposed on the butter ring, and means securing the buffer ring to the lower metal plate and to the annular metal ring. V p

The foregoing and other features of the invention set out in the appended claims are incorporated in the specific embodiments to be hereinafterparticularly described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a general view partly in section of a mine roof support according to the invention.

FIGURE 2'is a sectional view of part of FIGURE 1 with a pit prop leaning over.

FIGURE 3 is an end view of the mine roor" support with a pit prop leaning over laterally.

FIGURE 4 is a similar view to the sectioned part of FIGURE '1 showing a modification.

FIGURE 5 is a plan view of FIGURE 4. FIGURE 6 is a similar view to FIGURE 2 showing a further modification.

fld dfddl Patented June 8, I965 ice bearing surface 2a on which the prop can have pivotal movement by virtue of its part-spherical surface 1a.

For the purpose of resiliently biasing the prop into predetermined roof supporting relationship with the base bearing member 2, in this example perpendicular relationship, there is provided a rubber or the like buffer ring 3 extending about the pr-ops axis and secured between spaced abutmen-ts associated with the base bearing member .2 and the prop '1 respectively.

The abutment associated with the base bearing member 2 is constituted by a metal plate 2b of the base bearing member 2 encircling the prop 1, and the abutment associated with the prop ,1 is constituted by an annular metal ring 4a at the base of a tubular bearing member 4 encircling the prop 1.

The tubular bearing member 4 has a truncated conical tube 412 projecting upwardly from the metal ring 4a to an upper location remote from the base of the prop 1 where it terminates in an upper ring 40 closely encircling the prop ll.

The butler ring 3 is in effect sandwiched between the metal plate 2b of the base bearing member 2 and the metal ring 4a of the tubular bearing member 4, and the three parts 2b, 3 and 4a are secured together by circumferentially spaced bolts 5, the latter extending through enlarged holes 2c, 4d and 3a in metal plate 2b, the metal ring 4a, and buflfcr ring 3, respectively, with part-spherical seating washers 6, or other washers such for example as split or spring washers, provided behind the heads and nuts 5a, 5b of the bolts 5... I

The bolts 5 are sufficiently tight to pro-stress the butter ring'S into a state of compression causing a slight bulge 3b, 3c at inner and outer sides of the buffer ring 3.

In use of the mine roof support, the butter ring 3 acts between the metal plate 2b of the base bearing member 2 and the metal ring 4a of the tubular bearing member 4 to bias the prop 1 into an attitude in this example perpendicular to the base bearing member 2 when the support is not under load as in FIGURE 1.

After a period of use, i.e. with the support under load of the roof, audit the roof has had horizontal movement, this will cause the prop to tilt as in FIGURE 2.

An eifect of this is that a force will be applied by the prop to the upper ring 4c of the tubular bearing member 4 which imparts the force through the metal ring 2b to the butter ring 3 in a direction substantially parallel to the props axis thereby to load the rubber ring 3.

When next the support is released from the roof, the buffer ring 3 acts in the reverse direction on'the tubular bearing member 4 to return the prop to its originalattitude perpendicular to the base bearing member 2.

It is to be noted that in this construction of FIGURES 1 and 2 the buffer ring 3 is secured by the bolts 5 jointly to the metal plate 2b -ofjthe base bearing member 2 and to the metal ring 4a of the tubular bearing member 4 with the buffer 3 pro-stressed, and the latter feature obviates any tendency for parts to gape at one side of the prop direction such for example as laterally as shown in FIG- URE 3.

In the modification FIGURES 4, 5 the butter ring 3 is secured in part to the metal plate 2b of the base bearing member 2 and in part to the metal ring of the tubular bearing member 4.

More specifically the buffer ring 3 is sandwiched between intermediate metal rings 7, 8, and whereas bolts 9 secure these intermediate rings, with the bufifer ring 3 between them, to the metal plate 2b of the base bearing member 2 free of the metal ring 4a of the tubular hearing member 4 (the nuts a being accommodated in clear- 'ance holes 4d in the metal ring 41: of the tubular bearing member 4), the bolts 10 secure said intermediate rings 7, 8 with the buffer ring 3 between them to the metal ring 4a of the tubular bearing member 4 free of the metal plate 2b of the base bearing member 2.

The bolts 9, 10 alternate circumferentially around the prop (FIGURE 5) and whereas the bolts 9 (FIGURE 2) extend upwardly through enlarged holes 8a, 3a and 7a and have said nuts 9a, heads 9b and part-spherical seating 'washers 90, or other washers such as split or spring washers, the bolts 10 extend downwardly through enlarged holes 4a, 7a and 3a and have heads 10a and screw ends 10b screwing into the lower ring 8.

The bolts 9, 10 are sul'ficiently tight to pre-stress the butter ring 3 under compression similarly to the arrangement of FIGURE 1.

In the modification of FIGURE6 the butter ring 3 is bonded to the intermediate rings 7 and 8, and at all the securing locations, the lowermost intermediate ring 8 is secured to the metal plate 2b of the base bearing member 2 by screws such as 11, and the uppermost intermediate ring 7 is secured to the metal ring 4a of the tubular member 4 by screws such as 12. In this construction therefore the buffer ring 3 is secured jointly to the metal plate 2b of the base bearing member 2 and the metal ring 4a of the tubular member 4 in part by said bonding. One advantage of this is that various tilting movements of the prop will subject the bufi'er'ring 3 alternately to compression and tension, and another advantage is that the bonding acts as the desired seal against undesired penetration of foreign matter between the buffer 3 and the intermediate rings 7, 8.

Although the invention has been particularly described with reference to the lower end of a prop, it is to be understood that the upper end of the prop may be similarly constructed.

It is also to be understood that the mine roof support according to the invention may be in the form of a prop support embodying two or more similar pit props on a common base, as shown in FIGURE 1, or a single prop.

It is further to be understood that whereas the bufler ring is particularly described as a rubber or the like butter ring, the butter ring may be of any other suitable form.

What we claim is:

1. A mine roof support having a base bearing for the lower end of a pit prop, a lower metal plate supported from the base bearing and extending around the prop, a rubber or the like buffer ring disposed on the lower metal plate and encircling the prop, a'tubular member encircling the prop closely at its upper end and having at its lower end an annular metal ring encircling the prop and disposed on the butter ring, and means securing the butter ring to the lower metal plate and to the annular metal ring.

2. A prop end mounting, comprising an end bearing for an end of the prop, a stationary plate arranged for disposition about the prop, a movable tubular member arranged for disposition about the prop spaced axially from the stationary plate and having an end hole for closely encircling the prop, a buffer ring arranged for disposition about the prop between the stationary plate and the movable tubular member, and means securing the buffer ring and the movable tubular member to the stationary plate.

3. A prop end mounting as claimed in claim 2 wherein said means consists of circumferentially spaced screw bolts which are tightened to place the buffer ring under compression for sealing purposes.

4. A prop end mounting, comprising an end bearing for an end of the prop, a stationary member arranged for disposition about the prop, a movable member arranged for disposition about the prop spaced axially from the stationary member, a pair of ring plates arranged for disposition about the prop between the stationary and movable members, a buffer ring arranged for disposition about the prop between said ring plates and bonded to the latter, and means securing the ring plates with bonded buffer ring and the movable member to the stationary member.

5. A prop end mounting as claimed in claim 4 wherein said means consists of circumferentially spaced screw bolts whereof each of some screw bolts comprises a headed shank which extends through the movable member and through the adjacent ring plate and through the bonded butter ring and screws into the other ring plate, and whereof each of the other screw bolts comprises a headed shank which extends through the stationary member and through its adjacent ring plate and through the butter ring with a tail of the shank extending in a hole in the movable member, and a screw nut on the tail of the shank in said hole in the movable member and bearing against the ring plate adjacent said movable member. 7

6. A prop end mounting as claimed in claim 4 wherein said means consists of circumferentially spaced headed screws, whereof each of some headed screws extends through a hole in the stationary member andscrews into the latters adjacent ring plate, and each of the other headed screws extends through a hole in the movable member and screws into the latters adjacent ring plate.

7. A prop end mounting, comprising an end bearing for an end of the prop, a stationary member arranged for disposition about the prop, a movable tubular mem ber arranged for disposition about the prop spaced axially from the stationary member and having an end hole for closely encircling the prop, a pair of axially spaced ring plates arranged for disposition about the prop between the stationary member and the tubular member, a butter ring arranged for disposition about the prop between the ring plates and bonded thereto, and means for securing the ring plates with the bonded buffer ring and the movable tubular member to the stationary member.

8. A mine roof support, comprising a prop, a base hearing under the prop, a stationary plate supported from the base bearing and disposed about the prop spaced axially from the base bearing, a movable tubular member disposed about the prop spaced axially from the stationary member and having an upper end hole closely embracing the prop, a buffer ring disposed about the prop between the stationary member and the movable tubular member, and circurnferentially spaced screw means connecting the buffer ring and the movable tubular member to the stationary plate.

9. A mine roof support, comprising a prop, a top bearing for the top end of the prop, a stationary plate disposed'about the prop and spaced axially from the top bearing, a movable tubular member disposed about the prop spaced axially from the stationary plate and having a lower end hole closely embracing the prop, a buffer ring disposed about the prop'between the stationary plate and the movable tubular member, and circumferentially spaced screw means securing the bufler ring and the movable tubular member to the stationary plate.

10. A mine root support, comprising a prop, a base bearing under the prop, a pair of lower axially spaced membershaving holes for the prop, a butter ring disposed between the members with the prop extending through it 5 and through said holes, the lower one of said lower members being stationary and the upper one of said lower members being movable with tilting movements of the prop, means interconnectingsaid lower members and the buffer ring, a top bearing over the prop, a pair of upper axially spaced members having upper holes for the prop, an upper buifer ring disposed between these upper members with the prop'extending through the upper buffer ring and through said upper holes, the upper one of said upper members being stationary and the lower one members and the buffer ring.

6 7 References Cited by the Examiner UNITED STATES PATENTS 2,128,216 8/38 Armington 24822 2,130,497 9/38 Hueglin 24822 X 2,535,080 12/50 Lee 248358 2,591,461 4/52 Muller 24822 3,101,228 8/63 Olowinski 248358 X FOREIGN PATENTS 924,022 2/ 5 5' Germany. 1,012,520 4/52 France. 1,034,568 7/58 Germany.

CLAUDE A. LE ROY, Primary Examiner. 

1. A MINE ROOF SUPPORT HAVING A BASE BEARING FOR THE LOWER END OF A PIT PROP, A LOWER METAL PLATE SUPPORTED FROM THE BASE BEARING AND EXTENDING AROUND THE PROP, A RUBBER OR THE LIKE BUFFER RING DISPOSED ON THE LOWER METAL PLATE AND ENCIRCLING THE PROP, A TUBULAR MEMBER ENCIRCLING THE PROP CLOSELY AT ITS UPPER END AND HAVING AT ITS LOWER 